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1 | package DBIx::Class::ResultSetColumn; |
2 | use strict; |
3 | use warnings; |
4 | use base 'DBIx::Class'; |
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5 | use List::Util; |
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6 | |
7 | =head1 NAME |
8 | |
9 | DBIx::Class::ResultSetColumn - helpful methods for messing |
10 | with a single column of the resultset |
11 | |
12 | =head1 SYNOPSIS |
13 | |
14 | $rs = $schema->resultset('CD')->search({ artist => 'Tool' }); |
15 | $rs_column = $rs->get_column('year'); |
16 | $max_year = $rs_column->max; #returns latest year |
17 | |
18 | =head1 DESCRIPTION |
19 | |
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20 | A convenience class used to perform operations on a specific column of |
21 | a resultset. |
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22 | |
23 | =cut |
24 | |
25 | =head1 METHODS |
26 | |
27 | =head2 new |
28 | |
29 | my $obj = DBIx::Class::ResultSetColumn->new($rs, $column); |
30 | |
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31 | Creates a new resultset column object from the resultset and column |
32 | passed as params. Used internally by L<DBIx::Class::ResultSet/get_column>. |
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33 | |
34 | =cut |
35 | |
36 | sub new { |
37 | my ($class, $rs, $column) = @_; |
38 | $class = ref $class if ref $class; |
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39 | |
40 | $rs->throw_exception("column must be supplied") unless $column; |
41 | |
3f6cc7e4 |
42 | my $new_parent_rs = $rs->search_rs; # we don't want to mess up the original, so clone it |
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43 | |
44 | # prefetch causes additional columns to be fetched, but we can not just make a new |
45 | # rs via the _resolved_attrs trick - we need to retain the separation between |
46 | # +select/+as and select/as |
47 | for my $attr (qw/prefetch collapse/) { |
48 | for (qw/attrs _attrs/) { |
49 | delete $new_parent_rs->{$_}{$attr} if ref $new_parent_rs->{$_}; |
50 | } |
51 | } |
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52 | |
152002c4 |
53 | # If $column can be found in the 'as' list of the parent resultset, use the |
54 | # corresponding element of its 'select' list (to keep any custom column |
55 | # definition set up with 'select' or '+select' attrs), otherwise use $column |
56 | # (to create a new column definition on-the-fly). |
7ae9706c |
57 | my $attrs = $new_parent_rs->_resolved_attrs; |
58 | |
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59 | my $as_list = $attrs->{as} || []; |
60 | my $select_list = $attrs->{select} || []; |
61 | my $as_index = List::Util::first { ($as_list->[$_] || "") eq $column } 0..$#$as_list; |
b6e85b48 |
62 | my $select = defined $as_index ? $select_list->[$as_index] : $column; |
63 | |
64 | my $new = bless { _select => $select, _as => $column, _parent_resultset => $new_parent_rs }, $class; |
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65 | return $new; |
66 | } |
67 | |
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68 | =head2 as_query (EXPERIMENTAL) |
658fa250 |
69 | |
70 | =over 4 |
71 | |
428a645e |
72 | =item Arguments: none |
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73 | |
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74 | =item Return Value: \[ $sql, @bind ] |
658fa250 |
75 | |
76 | =back |
77 | |
78 | Returns the SQL query and bind vars associated with the invocant. |
79 | |
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80 | This is generally used as the RHS for a subquery. |
c7a9d102 |
81 | |
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82 | B<NOTE>: This feature is still experimental. |
83 | |
c7a9d102 |
84 | =cut |
85 | |
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86 | sub as_query { return shift->_resultset->as_query(@_) } |
c7a9d102 |
87 | |
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88 | =head2 next |
89 | |
90 | =over 4 |
91 | |
92 | =item Arguments: none |
93 | |
94 | =item Return Value: $value |
95 | |
96 | =back |
97 | |
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98 | Returns the next value of the column in the resultset (or C<undef> if |
99 | there is none). |
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100 | |
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101 | Much like L<DBIx::Class::ResultSet/next> but just returning the |
102 | one value. |
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103 | |
104 | =cut |
105 | |
106 | sub next { |
107 | my $self = shift; |
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108 | my ($row) = $self->_resultset->cursor->next; |
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109 | return $row; |
110 | } |
111 | |
112 | =head2 all |
113 | |
114 | =over 4 |
115 | |
116 | =item Arguments: none |
117 | |
118 | =item Return Value: @values |
119 | |
120 | =back |
121 | |
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122 | Returns all values of the column in the resultset (or C<undef> if |
123 | there are none). |
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124 | |
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125 | Much like L<DBIx::Class::ResultSet/all> but returns values rather |
126 | than row objects. |
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127 | |
128 | =cut |
129 | |
130 | sub all { |
131 | my $self = shift; |
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132 | return map { $_->[0] } $self->_resultset->cursor->all; |
133 | } |
134 | |
135 | =head2 reset |
136 | |
137 | =over 4 |
138 | |
139 | =item Arguments: none |
140 | |
141 | =item Return Value: $self |
142 | |
143 | =back |
144 | |
145 | Resets the underlying resultset's cursor, so you can iterate through the |
146 | elements of the column again. |
147 | |
148 | Much like L<DBIx::Class::ResultSet/reset>. |
149 | |
150 | =cut |
151 | |
152 | sub reset { |
153 | my $self = shift; |
154 | $self->_resultset->cursor->reset; |
155 | return $self; |
156 | } |
157 | |
158 | =head2 first |
159 | |
160 | =over 4 |
161 | |
162 | =item Arguments: none |
163 | |
164 | =item Return Value: $value |
165 | |
166 | =back |
167 | |
168 | Resets the underlying resultset and returns the next value of the column in the |
169 | resultset (or C<undef> if there is none). |
170 | |
171 | Much like L<DBIx::Class::ResultSet/first> but just returning the one value. |
172 | |
173 | =cut |
174 | |
175 | sub first { |
176 | my $self = shift; |
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177 | my ($row) = $self->_resultset->cursor->reset->next; |
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178 | return $row; |
2bb7b40b |
179 | } |
180 | |
181 | =head2 min |
182 | |
183 | =over 4 |
184 | |
185 | =item Arguments: none |
186 | |
187 | =item Return Value: $lowest_value |
188 | |
189 | =back |
190 | |
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191 | my $first_year = $year_col->min(); |
192 | |
193 | Wrapper for ->func. Returns the lowest value of the column in the |
194 | resultset (or C<undef> if there are none). |
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195 | |
196 | =cut |
197 | |
198 | sub min { |
6b051e14 |
199 | return shift->func('MIN'); |
2bb7b40b |
200 | } |
201 | |
4fa7bc22 |
202 | =head2 min_rs |
203 | |
204 | =over 4 |
205 | |
206 | =item Arguments: none |
207 | |
208 | =item Return Value: $resultset |
209 | |
210 | =back |
211 | |
212 | my $rs = $year_col->min_rs(); |
213 | |
214 | Wrapper for ->func_rs for function MIN(). |
215 | |
216 | =cut |
217 | |
218 | sub min_rs { return shift->func_rs('MIN') } |
219 | |
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220 | =head2 max |
221 | |
222 | =over 4 |
223 | |
224 | =item Arguments: none |
225 | |
226 | =item Return Value: $highest_value |
227 | |
228 | =back |
229 | |
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230 | my $last_year = $year_col->max(); |
231 | |
232 | Wrapper for ->func. Returns the highest value of the column in the |
233 | resultset (or C<undef> if there are none). |
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234 | |
235 | =cut |
236 | |
237 | sub max { |
6b051e14 |
238 | return shift->func('MAX'); |
2bb7b40b |
239 | } |
240 | |
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241 | =head2 max_rs |
242 | |
243 | =over 4 |
244 | |
245 | =item Arguments: none |
246 | |
247 | =item Return Value: $resultset |
248 | |
249 | =back |
250 | |
251 | my $rs = $year_col->max_rs(); |
252 | |
253 | Wrapper for ->func_rs for function MAX(). |
254 | |
255 | =cut |
256 | |
257 | sub max_rs { return shift->func_rs('MAX') } |
258 | |
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259 | =head2 sum |
260 | |
261 | =over 4 |
262 | |
263 | =item Arguments: none |
264 | |
265 | =item Return Value: $sum_of_values |
266 | |
267 | =back |
268 | |
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269 | my $total = $prices_col->sum(); |
270 | |
271 | Wrapper for ->func. Returns the sum of all the values in the column of |
272 | the resultset. Use on varchar-like columns at your own risk. |
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273 | |
274 | =cut |
275 | |
276 | sub sum { |
6b051e14 |
277 | return shift->func('SUM'); |
2bb7b40b |
278 | } |
279 | |
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280 | =head2 sum_rs |
281 | |
282 | =over 4 |
283 | |
284 | =item Arguments: none |
285 | |
286 | =item Return Value: $resultset |
287 | |
288 | =back |
289 | |
290 | my $rs = $year_col->sum_rs(); |
291 | |
292 | Wrapper for ->func_rs for function SUM(). |
293 | |
294 | =cut |
295 | |
296 | sub sum_rs { return shift->func_rs('SUM') } |
297 | |
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298 | =head2 func |
299 | |
300 | =over 4 |
301 | |
302 | =item Arguments: $function |
303 | |
304 | =item Return Value: $function_return_value |
305 | |
306 | =back |
307 | |
e8419341 |
308 | $rs = $schema->resultset("CD")->search({}); |
309 | $length = $rs->get_column('title')->func('LENGTH'); |
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310 | |
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311 | Runs a query using the function on the column and returns the |
312 | value. Produces the following SQL: |
313 | |
314 | SELECT LENGTH( title ) FROM cd me |
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315 | |
316 | =cut |
317 | |
318 | sub func { |
6b051e14 |
319 | my ($self,$function) = @_; |
4fa7bc22 |
320 | my $cursor = $self->func_rs($function)->cursor; |
5d62876f |
321 | |
322 | if( wantarray ) { |
323 | return map { $_->[ 0 ] } $cursor->all; |
324 | } |
325 | |
326 | return ( $cursor->next )[ 0 ]; |
2bb7b40b |
327 | } |
328 | |
4fa7bc22 |
329 | =head2 func_rs |
330 | |
331 | =over 4 |
332 | |
333 | =item Arguments: $function |
334 | |
335 | =item Return Value: $resultset |
336 | |
337 | =back |
338 | |
339 | Creates the resultset that C<func()> uses to run its query. |
340 | |
341 | =cut |
342 | |
343 | sub func_rs { |
344 | my ($self,$function) = @_; |
345 | return $self->{_parent_resultset}->search( |
346 | undef, { |
347 | select => {$function => $self->{_select}}, |
348 | as => [$self->{_as}], |
349 | }, |
350 | ); |
351 | } |
352 | |
5d1fc7dc |
353 | =head2 throw_exception |
354 | |
355 | See L<DBIx::Class::Schema/throw_exception> for details. |
356 | |
357 | =cut |
358 | |
359 | sub throw_exception { |
360 | my $self=shift; |
361 | if (ref $self && $self->{_parent_resultset}) { |
362 | $self->{_parent_resultset}->throw_exception(@_) |
363 | } else { |
364 | croak(@_); |
365 | } |
366 | } |
367 | |
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368 | # _resultset |
369 | # |
370 | # Arguments: none |
371 | # |
372 | # Return Value: $resultset |
373 | # |
374 | # $year_col->_resultset->next |
375 | # |
376 | # Returns the underlying resultset. Creates it from the parent resultset if |
377 | # necessary. |
378 | # |
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379 | sub _resultset { |
380 | my $self = shift; |
381 | |
382 | return $self->{_resultset} ||= $self->{_parent_resultset}->search(undef, |
383 | { |
384 | select => [$self->{_select}], |
385 | as => [$self->{_as}] |
386 | } |
387 | ); |
388 | } |
389 | |
2bb7b40b |
390 | 1; |
391 | |
392 | =head1 AUTHORS |
393 | |
394 | Luke Saunders <luke.saunders@gmail.com> |
395 | |
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396 | Jess Robinson |
397 | |
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398 | =head1 LICENSE |
399 | |
400 | You may distribute this code under the same terms as Perl itself. |
401 | |
402 | =cut |